Thought I'd mention this here, because with current gcc the use (or omission!) of -march in CFLAGS isn't doing what I had expected.
Background: my buildscripts are on nfs, as are my sources, so in the past I've found it convenient to bring up a new machine by building what I hope will be a suitable LFS on an existing system, fixing up the kernel, and then copying it over - usually followed by sorting out changes to video drivers / kernel config / hardware monitoring. The new box is my first Ryzen (nothing fancy, just an R3 1300X for four real cores with good cache sizes), and I was hoping to use the initial system to get to grips with whatever I may, or may not, need to do to get nouveau running. Recently I've been using -march=native in my CFLAGS (in the hope that compilation might be less slow), but for this build I dropped that and made sure that gmp used config.fsf. It booted fine on the build machine (a Kaveri, model 15h), but when I copied it over and tried to chroot from SystemRescueCD I got 'illegal instruction'. Eventually I dug out an OpenSuse disk and tried that in recovery mode: same result, but it told me the problem was in ld-2.27.so. Googling around, I came upon old gentoo threads where -march=k8 was recommended because Ryzens omit 4 instructions which were available on Excavator CPUs. Return to start, do not pass go, do not collect 200 currency-units. So, I tried that. But the same result. That is what really concerns me. Then I got lucky - saved the kernel, modules, .config and tried loading a backup from a different machine (an AMD Phenom - much earlier x86_64, I think that is fam 10h) - with that I could chroot from SystemRescueCD. Installed grub, fixed things up, booted. But that wasn't a minimal system, so I've deferred looking at whatever nouveau may, or may not, need for Xorg on this hardware (it's only a GT710 - the bottom of the range, no fan and a vga output). It is now getting towards the end of chapter 6 in a native build. I'm really mentioning this in case anybody else gets a Ryzen and tries the same approach. ĸen -- Before the universe began, there was a sound. It went: "One, two, ONE, two, three, four" [...] The cataclysmic power chord that followed was the creation of time and space and matter and it does Not Fade Away. - wiki.lspace.org/mediawiki/Music_With_Rocks_In -- http://lists.linuxfromscratch.org/listinfo/lfs-support FAQ: http://www.linuxfromscratch.org/blfs/faq.html Unsubscribe: See the above information page Do not top post on this list. A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail? http://en.wikipedia.org/wiki/Posting_style
